A New 3D Iodoargentate Hybrid: Structure, Optical/Photoelectric Performance and Theoretical Research

The explorations of new three-dimensional (3D) microporous metal halides, especially the iodoargentate-based hybrids, and understanding of their structure-activity relationships are still quite essential but full of great challenges. Herein, with the aromatic 4,4'-dpa (4,4'-dpa = 4,4'-dipyridylamine) ligands as the structural directing agents, we solvothermal synthesized and structurally characterized a novel member of microporous iodoargentate family, namely [H₂-4,4'-dpa]Ag₆I₈ (1). Compound 1 possesses a unique and complicated 3D [Ag₆I₈]² anionic architecture that was built up from the unusual hexameric [Ag₆I₁₃] secondary building units (SBUs). Research on optical properties indicated that compound 1 exhibited semiconductor behavior, with an optical band gap of 2.50 eV. Under the alternate irradiation of light, prominent photoelectric switching abilities could be achieved by compound [H₂-4,4'-dpa]Ag₆I₈, whose photocurrent densities (0.37 μA·cm^-2 for visible light and 1.23 μA·cm^-2 for full-spectrum) compared well with or exceeded those of some high-performance halide counterparts. Further theoretical calculations revealed that the relatively dispersed conduction bands (CBs) structures in compound 1 induced higher electron mobilities, which may be responsible for its good photoelectricity. Presented in this work also comprised the analyses of Hirshfeld surface, powder X-ray diffractometer (PXRD), thermogravimetric measurement, energy-dispersive X-ray spectrum (EDX) along with X-ray photoelectron spectroscopy (XPS).